1. Field of the Invention
The present invention relates to isolated polypeptides having alpha-L-arabinofuranosidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.
2. Description of the Related Art
Plant cell wall polysaccharides generally constitute 90% of the plant cell wall and can be divided into three groups: cellulose, hemicellulose, and pectin. Cellulose represents the major constituent of cell wall polysaccharides. Hemicelluloses are the second most abundant constituent of plant cell walls. The major hemicellulose polymer is xylan. The structure of xylans found in cell walls of plants can differ significantly depending on their origin, but they always contain a beta-1,4-linked D-xylose backbone. The beta-1,4-linked D-xylose backbone can be substituted by various side groups, such as L-aribinose, D-galactose, acetyl, feruloyl, p-coumaroyl, and glucuronic acid residues.
Biodegradation of the xylan backbone depends on two classes of enzymes: endoxylanases and beta-xylosidases. Endoxylanases (EC 3.2.1.8) cleave the xylan backbone into smaller oligosaccharides, which can be further degraded to xylose by beta-xylosidases (EC 3.2.1.37). Other enzymes involved in the degradation of xylan include, for example, acetylxylan esterase, arabinase, alpha-L-arabinofuranosidase, alpha-glucuronidase, feruloyl esterase, and p-coumaric acid esterase.
Kaji and Tagawa, 1970, Biochim. Biophys. Acta 207 456-464, describe the purification, crystallization and amino acid composition of an alpha-L-arabinofuranosidase from Aspergillus niger. Kaji. and Yoshihara, 1971, Biochim. Biophys. Acta 250 367-371, describe the properties of an alpha-L-arabinofuranosidase from Corticium rolfsii. Tagawa and Kaji, 1969, Carbohydr. Res. 11: 293-301, describe the preparation of L-arabinose-containing polysaccharides and the action of an alpha-L-arabinofuranosidase on the polysaccharides. Filho et al., 1996, Appl. Environ. Microbiol. 62: 168-173, disclose the purification and characterization of two alpha-L-arabinofuranosidases from Penicillium capsulatum. WO 96/06935 discloses an arabinoxylan degrading enzyme from Aspergillus niger. WO 2006/125438 describes a Penicillium capsulatum alpha-L-arabinofuranosidase and polynucleotide thereof.
The present invention relates to polypeptides having alpha-L-arabinofuranosidase activity and polynucleotides encoding the polypeptides.